1. Field of the Invention
The present invention relates generally to devices for assisting physically impaired persons in performing normal toilet functions. In particular, the present invention relates to a heavy duty power-assisted toilet seat lift assembly for assisting a person in being raised from and lowered onto a toilet.
2. Description of the Related Art
Physically impaired persons often have difficulty in performing normal toilet functions, such as being raised from and lowered onto a toilet. Health care providers are often relied upon to help position physically impaired persons on a toilet and to lift the persons from the toilet. Lifting of physically impaired persons by health care providers has often caused strained backs and other injuries to the health care provider, as well as to the person being assisted.
A variety of designs for powered lift toilet seats have been disclosed in the prior art. For example, U.S. Pat. No. 4,587,678, issued to Love et al., discloses a stationary frame with fixed handrails. A seat assembly is pivotally coupled to the stationary frame, and an electric motor and lift arms are provided for pivotally moving the seat frame assembly relative to the stationary frame. While the toilet seat assembly of Love et al. has a pivoting seat assembly, a vertically movable toilet seat has also been disclosed, for example, in U.S. Pat. No. 3,925,833 issued to Hunter. Hunter employs a hydraulic cylinder for raising and lowering the seat.
Another version of an electrically operated toilet seat is disclosed in U.S. Pat. No. 5,155,873 issued to Bridges. Bridges discloses armrests that can be swung out of the way to enable an attendant to assist a disabled person in using the device. Another form of hydraulically powered lift seat is disclosed in U.S. Pat. No. 4,993,085 issued to Gibbons. Gibbons discloses a pair of hydraulically operated lift assemblies with associated armrests that are tilted to cause the armrests to move in an upward and forward position as the mechanism is operated. The seat is provided with a second pair of hydraulically operated lifts to tilt the seat up and forward as the lift assemblies are operated.
Other powered lift toilet seats have been disclosed that include mechanical linkages that allow the seat to tilt while moving upward and forward. For example, U.S. Pat. No. 4,581,778 issued to Pontoppidan discloses a mechanism comprising two supporting arms that are coupled at one of their ends to the seat and cooperate at their other end with a fixed point and a driving member to provide a tilting motion while moving upward and forward. Another such powered lift toilet seat is disclosed in U.S. Pat. No. 5,661,858 issued to House et al., which uses a gear mechanism to lift and move forward the front of the toilet seat and a lever action to cause the rear of the toilet seat to rise and tilt forward with respect to the front of the seat. A linear actuator is provided to effect the gear and rear lever action.
While the conventional powered lift toilet seats described above provide an improvement over manual lifting of physically impaired persons, these devices suffer from several disadvantages. For example, the powered lift toilet seat of House et al. cannot be used with a conventional toilet because the actuator, gear and linkage mechanisms are arranged such that they would interfere with positioning the toilet seat over a conventional toilet. Instead, the toilet seat of House et al. includes its own built-in toilet bowl. The powered lift toilet seats of Love et al., Hunter, Bridges, and Gibbons fail to provide a powered lift toilet seat that tilts while moving upward and forward. Thus, these devices are difficult to use and ineffective for many physically impaired persons, making them unsuitable for many applications. The toilet seat lift of Pontoppidan provides a seat movement during lifting that is physiologically improved over those of Love et al., Hunter, Bridges, and Gibbons. However, the linkage mechanism disclosed by Pontoppidan includes sliding connections that result in a high friction loss and reduced stability during operation.
Thus, there is a need in the health care industry for an improved power assisted toilet seat that provides an optimum movement with increased stability for raising a physically impaired person from a toilet and assisting the person to sit on the toilet.